Oh, forgot to mention that the Druid's Altar is usually marked on maps as a cairn, but in my view, no way - it's a 4Poster. But it's pretty deffo not this one - too far away & wrong direction I'm sure.
I believe the henge shown north of Grassington is a pretty ploughed out earthwork and may indeed be a henge. Never got round to looking for it tho. Interestingly tho, I seem to remember it IS supposed to be south of an "ancient settlement" & field systems (which I HAVE seen) by a limestone pavement on the main path over to Conistone.
Bet that dunt help at all! ;^)
Brigantesnation MAY also know summat. I know he's been to at least some of the stuff round there - eg the Druid's Altar. (Tho he disagrees with everyone & thinks that's the remains of a burial chamber rather than a 4 poster.)
love
Moth